This application claims the priority of DE 100 09 128.8 filed Feb. 26, 2000 and entitled Vehicle Seat Ventilating System.
The invention relates generally to a device for ventilating a vehicle seat and, more particularly, concerns a fan-ventilated seat controlled by a central seat control unit.
Ventilated vehicle seats serve to improve seat comfort. Optimum temperature distribution within the vehicle seat can be achieved by means of one or more fans arranged in the vehicle seat, and ventilation can also be used to avoid seat overheating resulting from direct exposure to sunlight. As used herein, the term xe2x80x9cseatxe2x80x9d or xe2x80x9cseating surfacexe2x80x9d or xe2x80x9cseating ventilationxe2x80x9d is intended to include both seats in the narrow sense and seat back rests or supports.
U.S. Pat. No. 5,902,014 describes a vehicle seat equipped with a ventilation layer on the upholstery covering of the vehicle seat. A plurality of electrically driven miniature fans integrated in the upholstery covering, which can be switched on and off by the seat user, are provided in order to ventilate the ventilation layer.
U.S. Pat. No. 5,934,748 describes a vehicle seat with a central control unit for the actuation of fans arranged in the vehicle seat. The central control unit operates as a function of the upholstery surface temperature in order to switch the fans to the appropriate power level.
The foregoing systems have drawbacks in that they are highly customized for each particular application. Furthermore, because all fans are controlled from a central unit, interference in the transmission lines connecting the fans to the central control unit can degrade the overall system performance. Accordingly, there exits a need for a vehicle seat ventilation system having improved communication integrity and a standardized, and hence readily scalable, architecture.
Accordingly, an object of the present invention is to provide a device for ventilating a vehicle seat having simplified architecture and a high degree of integrity in the communication pathways between the fans arranged in the vehicle seat and the central seat control unit.
According to one embodiment of the present invention, the foregoing and other objects and advantages are attained by a vehicle seat ventilating system comprising at least one fan arranged in the seat and controlled by a central control unit and an electric control unit associated with each fan for actuating the respective fan in response to control signals from the central control unit, wherein each electronic control is arranged at the respective fan. Thus, each of the fans arranged in the vehicle seat has its own electronic control unit that is located at the fan and is connected to the central seat control unit by a data line that transmits control signals. The power supply currents required to drive the fan are regulated directly in the electronic control unit located at the respective fan.
An advantage of the present invention is that the electronic control unit located at the fan can be electromagnetically shielded in a very simple manner. Preferably this is accomplished by enclosing the electronic control unit in a metallic or metallized fan housing. Another advantage is that the data line leading to the fans carries only very low currents. As a result, the data line emits no significant interfering fields. In addition, the device in accordance with the invention has the advantage that, in accordance with the specific requirements, the data line can be connected to more or fewer fans, each of whose electronic control units can be addressed via the data line.
A further advantage of the present invention is that, the standard equipment of a motor vehicle can have a central seat control unit that is ready for connection to a data line leading to the fans. The standard equipment of the vehicle can then be expanded without difficulty in that fans, whose associated electronic control units need only be connected to the central seat control unit via a data line, are built into the driver""s seat or other vehicle seats as desired. Each fan with its electronic control unit then only needs to be connected to the on-board voltage supply.
The electronic control unit arranged at the fan can in each case serve as a serial interface between the fan drive and the central seat control unit.
The data line between the central seat control unit and the electronic control unit is preferably designed as a bidirectional data bus that is capable not only of transmitting control signals to the electronic control unit of the fan, but also communicate data on-operating conditions and data on the temperature of the transported air to the central seat control unit. Based on the data received, the central seat control unit can operate the individual fans or perform a fault diagnosis on the individual fans.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.